Double process of photographic reproduction



Patented Feb. 5, lg dl.

entree srarrs PATENT orrrcr.

ROBERT JOHN, 015 NEW? YORK, N. K, ASSIGNOR T DAYLIGHT FILM COBJPQRATION, A

. CORPORATION OF NEW YORK.

DOUBLE PROGEQS 0F PHOTOGRAPHIC REPRODUCTEQN.

No Drawing.

To all whom it may concern:

Be it known that 1, ROBERT JoH'N, a citizen of the United States, residing at New York, in the county of New York and State 5 of New York, have invented a certain new and useful Double Process of Photographic Reproduction, of which the following is a specification.

My invention relates to a double process of photographic reproduction and has for its obj cct to produce a printing surface containing a photographic record of lights and shades from which copies can be made by a dye or ink contact transfer process. An illustrative dye contact transfer process is disclosed in patent to Shepherd and Bart-- lett, No. 728,310, granted May 19, 1903, for

photographic printing, and an illustrative ink contact transfer process is disclosed in Cassells Cyclopaedia of Photography, Gassell & 00., New York, 1912, at page 124' under the title Collot pe, it bein understood, however, that t e processes t us illus trated do not disclose a rinting plate having the novel and bene cial characteristics of the printing plate obtained by. the process disclosed and claimed herein. Although the preferred method is to obtain the photographic record for the printing surface so from a completed negative, it may be obtained by direct exposure, as, for example, in a camera, the details of which method are disclosed in a copending application for Letters Patent Serial No. 327,890, filed October 2, 1919, for process of photographic re reduction directly from a negative. he printing surface when treated with dye or ink also may be used in the same manner as a positive, eitherfor direct view, or with reflected light, or with transmitted light as in a projecting machine.

The invention isapplicable to monochromatic, polychromatic, or natural color photography both in still photograph and in motion picture photography. The term color is intended to include black, which sometimes technically is designated as an absence of color.

In the embodiment of my invention chosen for purposes of illustration, a sensitized emulsion such as a silver salt emulsion is exposed to the action of light modified by the li hts and shades of thecompleted negative which it is desired to reproduce. The silver Application filed November 10, 1919. Serial H01 eaaeae.

salt emulsion may be carried or mounted on any desired support, either opaque, translucent, or transparent, but 7 preferably is mounted on a transparent carrier such, for example, as glass or a cellulose base in order that the silver salt emulsion may be exposed to the modified light through its transparent carrier.

The emulsion then is developed, either wholly or partially, by any non-hardening developer until a desirable metallic silver image .is obtained and preferably is suitabl fixed to removethe unreduced silver salt. he term non-hardening developer is intended to include a developer which does not harden the emulsion at all and a developer which hardens the emulsion only partially.

The emulsion then is treated by any well known converting agent, such, for example,

Potassium bichromate figrains Hydrochloric acid 1 minim Water 1 ounce thereby convertin or transforming the metallic silver bac to a chloride, bromide, or iodide of silver, or to some other silver salt, corresponding to the character of the converting agent. The emulsion thus contains only light-sensitive silver salts correspondingto the photographically recorded me e.

T e emulsion then is exposed to an actinic light and treated by a developing solution containing a hardening or tanning agent which renders insoluble or unremovable the emulsion adjacent its light-adected, light-sensitive content, the efiect of which a cut is controlled or limited selectively by t e presence of varying uantities or a neutralizing agent, after w ich the soluble or removable portions of emulsion may be removed in any desired manner, as for example, by melting With warm water. .With some converting agents, such, for example, as-

Potassium ferricyanide tigrains Potassium bromide .9grains Water 1 ounce tent in'condition to be developed and the emulsion hardened without this additional exposure. It is to be understood, therefore, that in carrying out the process, the additional exposure is included when this step is necessary in order to secure proper reaction for the hardening process.

The result of the above treatment is the production of what may be termed a printing surface having novel characteristics and beneficial properties never before attained. The double process also increases the control which may be exercised over the final relief obtained.

The most important of the novel characteristics is a printing or reproducing surface comprising granules or great numbers of photographically formed, extremely minute, individual protuberances which are distributed and grouped irregularly so as to represent photographic lights and shades.

The most important of the beneficial properties is that such a printing surface when treated with a dye, ink, or other coloring matter, will absorb or take up or carry the coloring matter within a few seconds, and

' when thus treated and placed in contact with a substance which is to carry the final reproduction, such for example as a gelatin, will give up its coloring matter practically instantaneously and produce on said gelatin an exact and perfect reproduction. This speedy result, which is novel and was impossible of attainment before the present invention, is of prime importance in the production of motion picture positives from motion picture negatives, although the savin of time and the superior results obtainab e in still photography also are important. The printing plate or film, moreover, when treated with coloring matter, may be used as a positive if reproductions are not desired.

A sample formula for a developing solution containing a hardening or tanninn agent the effect of which is controlled an limited selectively by the presence of varying quantities of a neutralizing agent is as follows:

8.5 ounces Water Pyrogallic acid 11 grains Metol 9 grains Potassium bromide .4 grains Sodium carbonate 200 grains Sodium sulphite 40 to 60 grains Metol is monomethylparamidophenolsulphate. In the above sample formula the hardening or tanning agent is pyrogallic acid, and

the controlling and limiting agent is sodium it may be used separately if and other neutralizing agents may be used, the above formula representing one developing solution by-which the process may be carried out. Potassium bromide, for example, also has a certain controlling and limiting effect. The main difference between the above sample formula and standard developing formulas is in the amount of sodium sulphite used. In standard formulas the amount of sodium sulphite. used is so greatly in excess of the amount used in the above sample formula that the tanning or hardening effect of the pyrogallic acid is entirely neutralized or overcome. In the sample formula, the sodium sulphite merely controls and limits the hardening effect of the pyrogallol. It is of course understood by those skilled in the art that when a thick layer of emulsion is treated, or when the exposure is through the transparent carrier, it is advisable, in order to accelerate the ation of the pyrogallic acid, to use larger quantities of an accelerator such, for example, as sodium carbonate or its equivalents than when the emulsion layer is thin or expose-:1 on its face; When larger quantities of sodium carbonate thus are used, it is necessary to increase the amount of sodium-sulphite. The above sample formula is for treatment of an emulsion exposed through its transparent carrier and therefore contains a comparatively large amount of sodium carbonate with an increased amount of sodium sulphite. In order to obtain the desired printing surface, however, the amount of sodium sulphite in the process disclosed herein is much less than would be used in a developing solution for the usual development of the particular emulsion layer to be treated. Although it is preferable for reasons of convenience to embody the selectively controlled hardening agent in the developer solution, desired, by such modification of the developer solution as will prevent such a hardening of the emulsion as will revent the selective hardening desired.

It is believed that the hardening or tanning effect of the pyrogallic acid exerts its action first adjacent the sc-called latent image, or in other Words, on the portion of emulsion adjacent the particles of silver salts affected by the exposure light and converted by the developer into metallic silver. Thus in a silver bromide film, the throwing oil of the bromide from a Iight-afiect-ed silver bromide particle in the developing process, probably reacts with the pyrogallic acid to harden or tan or render insoluble or unremovable the adjacent emulsion. .Thus in the embodiment chosen for purposes of illustration, the reaction products from the chemical efl'ects of the developer solution, are believed to react with the selectively controlled hardening agent. However this may be, it is necessary for purposes of my invention only and of the neutralizing agent being such as to ontrol selectively the efiective area of influence of the hardening agent. The unhardened portions, as stated above, then may be removed in any desired manner as by placing the emulsion in warm water which causes the unhardened or soluble portions to soften and melt away from the hardened or insoluble portions o that the hardened emulsion alone will remain in the form'of extremely minute, individual protuberances which are distributed and grouped irregularly so as to represent the hotographic lights and shades which it is esired to reproduce. It is preferable that only those portions of emulsion be hardened which are adjacent the carrier for the emulsion, which may be accomplished in various ways, some of which are disclosed in my copending a plications for Letters 313,239, filed July 25, 1919, for a thin mounted sensitized emulsion; Serial No. 313,240, filed July 25, 1919, for process of making a contact transfer printing surface by complementary light; Serial No. 327,891, filed October 2, 1919, for potassium iodide formula'for photographic processes, process of Y posureof the sensitized emulsion uslng same, and article obtained thereby; Serial No. 332,806, filed October 23, 1919, for process of making a contact transferprinting surface with a colored emulsion, and among which may be mentioned the exthrough its transparent carrier and the limitation of the depth to which the rays of exposure light penetrate by having the actinic rays of the exposure light and the emulsion comple mentary in color.

Although the emulsion already has been fixed, it may be fixed again if necessary, and

bleached to remove the black metallic silver. This may be done in well known manner, and while not necessary, is of advantage as it enables the operator of the coloring matter on the printing surface -to which it is applied for carrying out the-printing proce The order of melting,.bl eaching, and fixmg is not important and may be carried out i in any order desired, althoughit generally neeae ic- Patent Serial 0.

to watch the efi'ect I is more convenient to fix, melt, and bleach,

pressure, with the substance on which the 3 positive is to be made, as by a roller or by a squeegee action. As stated above, the printing surface prepared by my process receives and gives up the coloring matter almost instantly as distinguished from other processes which take an appreciable length of time.

Natural color effects ma be produced in well known manner, such fibr example as by exposure through color screens with subsequenttreatment and manipulation to obtain the desired results.

Many modifications of my invention will be apparent to those skilled in the art without departing therefrom or from the scope of the claims, my invention not being limited to the embodiments thereof chosen for purposes of illustration but consisting of a double process for forming a printing surface capable of acquiring and giving up a desired color with great rapidity.

Having described one embodiment of my invention, what I claim is:

1. The process of forming a photographic record of. lights and shades capable of use as a transfer printing plate, which comprises developing an exposed photographic emulsion with a. non-emulsion-hardening solution, fixing the undeveloped light sensitive content, converting the developed image so that it again becomes light sensitive, exposing it to, an actinic light, and then hardening portions of emulsion adjacent the light afl'ected sensitive content of the emulsion with an agent adapted to harden said emulsion by reaction with the light afiected sensitive content of the emulsion, and with a neutralizing agent for said hardenin agent, the relative proportions of sai hardening and neutralizing agents being such as to control selectively the effective area ofsinfluence of the hardening agent but to-an extent less than the complete neutralization of said hardenin agent.

2. The process speci ed in claim 1 in which the exposed sensitive emulsion is en tirely undeveloped prior to said treatment.

3. The process specified in claim 1 in which the hardening agent also is a developing agent.

a. The process specified in claim 1 in which the hardening agent is pyro allic acid.

5 The process specified in caim 1 in which the neutralizing agent also is a preservati've.

6. The process specified in claim 1 in which the neutralizing agent is sodium sulphite.

7. The process specified in claim 1 in which the hardening agent also is a developing agent and in which theneutralizcomprises developing an exposed photographic emulsion with a non-emulsionin agent also is a preservative.

8. The process specified in claim 1 in which the hardening agent is pyrogallic acid and the neutrallzing agent is sodium sulphite.

9. The process specified in claim 1 in which the sensitive content is developed at the same time the portions of emulsion adjacent thelight affected sensitive emulsion are hardened.

10. The process of forming a photographic record of lights and shades capable of use as a transfer printing plate, which comprises developing an exposed photographic emulsion with a non-emulsion hardening solution, fixing the undeveloped light sensitive content, converting the developed image so that it again becomes light sensitive, and hardening portions of the emulsion adjacent the light affected sensitive content with an agent permitting only a selective area of hardening and forming minute protuberances grouped irregularly to represent photographic lights and shades.

11. The process of forming a photographic record of lights and shades capable of use as a transfer printing plate, which hardening solution fixing the undeveloped light sensitive content, converting the developed image so that it again becomes light sensitive, and hardening portions of the emulsion adjacent the light affected sensitive content, with an agent adapted to harden said emulsion in combination with an agent having a neutralizing efiect on the hardening agent, the relative proportions of said agents being such as to prevent complete neutralization of the hardening agent and thereby form minute protuberances grouped irregularly to represent photographic lights and shades.

In testimony that I claim the foregoing, I have hereunto set my hand this 7th day of November, 1919.

RUBERT JOHN. 

